Browsing by Author "Hills, A. P."

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Association between early weight gain and later adiposity in Sri Lankan adolescents
(Cambridge University Press., 2021) Samaranayake, D.; Lanerolle, P.; Waidyatilaka, I.; de Lanerolle-Dias, M.; Hills, A. P.; Wickremasinghe, A.R.; Wickramasinghe, V.P.
ABSTRACT: Early growth pattern is increasingly recognized as a determinant of later obesity. This study aimed to identify the association between weight gain in early life and anthropometry, adiposity, leptin, and fasting insulin levels in adolescence. A cross-sectional study was conducted in 366 school children aged 11-13 years. Weight, height, and waist circumference (WC) were measured. Fat mass (FM) was assessed using bioelectrical impedance analysis. Blood was drawn after a 12-h fast for insulin and leptin assay. Birth weight and weight at 6 months and at 18 months were extracted from Child Health Development Records. An increase in weight SD score (SDS) by ≥0.67 was defined as accelerated weight gain. Linear mixed-effects modeling was used to predict anthropometry, adiposity, and metabolic outcomes using sex, pubertal status, accelerated weight gain as fixed factors; age, birth weight, and family income as fixed covariates, and school as a random factor. Children with accelerated weight gain between birth and 18 months had significantly higher body mass index (BMI) SDS, WC SDS, height SDS, %FM, fat mass index (FMI), fat free mass index (FFMI), and serum leptin levels in adolescence. Accelerated weight gain between 6 and 18 months was associated with higher BMI SDS, WC SDS, %FM, and FMI, but not with height SDS or FFMI. Accelerated weight gain at 0-6 months, in children with low birth weight, was associated with higher height SDS, BMI SDS, WC SDS, %FM, and FMI; in children with normal birth weight, it was associated with BMI SDS, WC SDS, height SDS, and FFMI, but not with %FM or FMI. Effects of accelerated weight gain in early life on anthropometry and adiposity in adolescence varied in different growth windows. Accelerated weight gain during 6-18 months was associated with higher FM rather than linear growth. Effects of accelerated weight gain between 0 and 6 months varied with birth weight. KEYWORDS: Early accelerated growth; adiposity; adolescence; birth weight; insulin; leptin; obesity.
Develepment and validation of a BIA prediction equation for 11-13 year old Sri Lankan girls
(Sri Lanka Medical Association, 2018) Samaranayake, D.; Dabare, H. P. M.; de Lanerolle-Dias, M.; Waidyatilaka, I.; Jayawardena, R.; Hills, A. P.; Wickremasinghe, A.R.; Lanerolle, P.; Wickramasinghe, V.P.
INTRODUCTION AND OBJECTIVES: Population-specific measures of body composition are important in management of childhood obesity. This study aimed to develop and validate a bioelectrical impedance analysis (BIA) equation to assess total body water (TBW) and fat mass (FM) in Sri Lankan girls aged 11-13 years. METHODS: Forty-six 11-13 year-old healthy school girls were purposively selected and randomly divided into model development (n=30) and model validation (n=l6) sub-samples. Weight, height and impedance using BIA were measured. TBW was determined and FM was derived through the criterion Deuterium-dilution technique. Prediction equations for TBW and FM were developed using impedance index (heightvimpedance; cm2/Q), weight and height as independent variables. Final equations were developed combining the two sub-samples. Validity was assessed using correlation coefficients, paired-samples T-test and Bland-Altman plots. RESULTS: In the validation sample, predicted TBW and FM showed significant correlations and did not significantly differ from reference values, Final prediction equation for TBW had a R2 of 92.3% and RMSE of l.035 while FM prediction equation had a R2 of 94.3% and RMSE of 1.38. TBW predicted from new equation (19.48± 3.45kg) was not significantly different from reference TBW (19.52±3.65kg) and the two measures were significantly correlated (r=0.975, p<0.001). Similarly, predicted FM (10.41±4.39kg) was not significantly different from reference FM (10.38±4.74kg) and predicted and reference values were significantly correlated (r=0.974, p<0.001). In both prediction equations, the majority ofresiduals were within mean± l.96SD. CONCLUSION: Newly developed prediction equations for BIA assessment of TBW and FM show high validity compared to reference technique.
Validity of BIA prediction equations in determining the fat mass of 11-13 year old Sri Lankan girls
(Sri Lanka Medical Association, 2018) Samaranayake, D.; Dabare, H. P. M.; de Lanerolle-Dias, M.; Waidyatilaka, I.; Jayawardena, R.; Hills, A. P.; Wickremasinghe, A.R.; Wickramasinghe, V.P.; Lanerolle, P.
INTRODUCTION AND OBJECTIVES: Bioelectrical impedance analysis (BIA) is a simple body composition assessment method, based on use of prediction equations. Validation of equations for the specific populations is important for accurate assessment. This study aimed to determine the validity of available BIA equations in assessing the fat mass (FM) in Sri Lankan girls aged 11-13 years. METHODS: Forty-six 11-13 year-old healthy school girls were purposively selected. Weight, height and impedance using BIA were measured. Total body water was determined and FM was derived through the criterion Deuterium dilution technique. Twelve BIA prediction equations applicable to the age and sex were identified from literature. Predicted FM calculated according to each equation was compared with reference FM (assessed through isotope dilution), and validity was assessed using correlation coefficients, paired samples T-test and Bland-Altman plots. RESULTS: FM predicted by all twelve equations was significantly correlated (r>0.93, p<0.05) with reference FM. Mean (±SD) bias of predicted FM ranged from -5.32 (±1.79) kg to 5.8 (±2.1 l) kg. Only four equations predicted mean FM values that were not significantly different from the mean reference FM values, the mean bias (±SD) ranging from -0.21 (±2.23) kg to 0.06 (±l.72) kg. Of these four prediction equations, only one had a symmetric, uniform distribution of error within the ±l .96 SD limits in the Bland-Altman analysis. CONCLUSION: Most available BIA prediction equations are unsatisfactory for use in the local context. Cross validation of existing prediction equations before use or development of BIA prediction equations to suit the local populations is recommended.